1. Field of the Invention
The present invention generally relates to an electromagnetic field controlling system and method. More particularly, the present invention relates to an electromagnetic field controlling system and method for a vehicle wireless charging system, which controls the magnitude of an electromagnetic field within a safe range, output from a wireless charging system of a vehicle requiring charging of a battery, such as an electric vehicle and a hybrid electric vehicle.
2. Description of the Related Art
Generally, electric vehicles have a driving motor that is driven by battery power as a power source. A hybrid electric vehicle also includes an engine as a power source. Further, electric vehicles have improved fuel efficiency by using auxiliary power of the motor operated by the battery power when the vehicle is started or accelerated. Particularly, the electric vehicle includes an electric vehicle (EV) that has a battery and a motor driven by battery power and that uses motor torque as a power source, a hybrid electric vehicle (HEV), a range extended electric vehicle (RE-EV), and the like. In other words, an electric vehicle includes the above-described three forms of vehicles and all the vehicles having a battery and a motor that is used as a power source by using battery power.
A technology adaptable to applications requiring a substantial amount of power, for example, battery charging applied to an electric vehicle, plug-in hybrid vehicle, and the like, has been developed. In an electric vehicle, the high capacity battery is required to be charged frequently for driving, and currently, wired charging, in which a plug for transmitting electric power is inserted to a charging inlet of the vehicle, is commonly used.
However, to solve problems of inconvenience with wired charging, wireless charging is actively being researched. Wireless charging technology is based on transmitting and receiving electric power using electromagnetic induction or resonance. To implement wireless charging, wireless charging devices having coils are required in both a power transmission side and a power receiving side. In particular, in wireless charging devices for charging electric vehicles or plug-in hybrid vehicles, since a substantial amount of electric power is required to be transmitted to reduce the battery charging time of a high capacity battery, unwanted electromagnetic waves (e.g., electromagnetic field), which may adversely affect the human body, adjacent electromagnetic instruments, and the like, may be produced.